Conventionally, there is proposed a power supply system in which power generation is performed by a fuel cell installed in a vehicle and an electric power is supplied to a household electrical appliance, i.e., the power supply system which performs so-called external power feeding. For example, Japanese Laid-Open Patent Publication No. 2014-060068 (hereinafter referred to as “Patent Document 1”) proposes a technique that detects a dry state of the fuel cell during the external power feeding, and drives a radiator fan to avoid a so-called dry-up state when the fuel cell is in the dry state.
By the way, it is considered that, when the external power feeding is performed by the fuel cell installed in the vehicle, the vehicle is in a stop state, so that a traveling wind cannot be introduced into the radiator and the fuel cell cannot be cooled appropriately. A power supply system disclosed in the Patent Document 1 sends a wind to the radiator by driving a fan, and hence can cool the fuel cell. However, an electric power is consumed by the drive of the fan. In this respect, the power supply system disclosed in the Patent Document 1 has room for improvement.